The invention concerns a diffractometer, comprising a source for generating X-ray radiation, a sample position for arranging a sample, and a detector for detecting X-ray radiation emitted by the sample, wherein the source and the detector can be rotated with respect to an axis A that extends through the sample position, and wherein the source, the sample position, and the detector are disposed in a common plane M that extends perpendicularly to the axis A.
A diffractometer of this type is disclosed e.g. by the document JP6066741.
X-ray diffractometry is used in a plurality of ways in order to analyze crystalline (and to a certain degree also amorphous) components of samples. X-ray radiation is thereby diffracted on crystal planes in the sample. The spatial intensity distribution of the diffracted X-ray radiation, in particular the position of intensity maxima (“reflexes”) can e.g. give information about the interlattice plane distance and thereby about the crystal lattice (lattice symmetry) or also about preferred lattice plane orientations (textures). The basic connection between the interlattice plane distance, the angle of incidence and the wavelength of X-ray radiation is described by Bragg's law.
In X-ray diffraction experiments, the normal to the observed lattice plane group forms the bisector of the incident and emergent X-rays. An overall X-ray measurement for determining an X-ray data set consists of many individual measurements of integral intensities with different beam geometries. During one overall X-ray measurement, which comprises many integrals of individual measurements, the X-ray source and/or the X-ray detector are correspondingly moved and/or the sample is tilted.
In some measuring methods, in particular, when tilting of the sample shall be prevented during an X-ray measurement, both the source and the detector must be moved around the sample on respective circular arcs during the overall X-ray measurement (measurement of one data set).
An X-ray diffractometer with a source that can be moved on a first circular arc and a detector that can be moved on a second circular arc is disclosed in JP6066741. In conventional devices, the source and the detector are normally each driven by their own motor, and the movements are synchronized through electronic control of the two motors in accordance with the requirements of the measuring method, generally in a Θ-Θ-geometry or Θ-2Θ-geometry. In another conventional method, the source as well as the detector are moved via two separate transmissions by only one motor.
In both cases, the diffractometer construction is quite complex and therefore expensive.
It is the underlying purpose of the invention to present a diffractometer having a greatly simplified construction, in which the source and the detector can be moved on circular arcs in accordance with a Θ-Θ-geometry.